QRSS and DFCW signals (March 9, 2003)

The above image of the top part of the LF amateur band was taken on a sunday morning and shows quite a bit of activity from G3XDV, DL2HRE, S57A, DF8ZR, I5TGC, DK1IS (50 km from me), OH5UFO, YU7AR and IK5ZPV. Background signals are DBF39 FSK-bursts every 10 s (purple vertical lines), the continuous carrier on 137689.6 (yellow) and a sample-rate alias of DBF39's carrier.